Human odometry verifies the symmetry perspective on bipedal gaits

Area of Science:

• Biomechanics
• Dynamical Systems Theory
• Human Locomotion

Background:

• Bipedal gaits are classified by the symmetry of their underlying mathematical models.
• Primary gaits exhibit dihedral symmetry, while secondary gaits show cyclic symmetry.

Purpose of the Study:

• To investigate the impact of gait symmetry on human odometry.
• To model human distance estimation using principles from dynamical systems.

Main Methods:

• Classifying bipedal gaits based on group symmetry of differential equation networks.
• Testing human odometry by having participants measure and report distances using different gait symmetries.
• Modeling sequential behaviors using concepts from parallel behavior dynamics.

Main Results:

• When gait symmetry classes are consistent between measurement and reporting, primary and secondary gaits yield comparable distance estimates.
• Switching from primary to secondary gait symmetry compresses perceived distance.
• Switching from secondary to primary gait symmetry inflates perceived distance, with equal magnitude of compression and inflation.

Conclusions:

• Human odometry dynamics involve sequential measure and report phases.
• Relative velocity acts as an order parameter, while gait symmetry class difference functions as a detuning parameter.
• Gait symmetry is a critical factor influencing the accuracy of human distance perception.